Electric-arc lamp



(No Model.) 2 Sheets-Sheet 1.

J. R. FINNEY.

ELEOTRIG ARC LAMP.

No. 268,594. Patented Dec. 5, 1882.

WJmeSSes fi e mm m A4 z/o w (No Model.) 2 Sheets-Sheet 2. J. R. FINNEY.

ELECTRIC ARC LAMP.

No. 268,394. Patented Dec. 5, 1882.

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. made Ofgaspipe, and is secured to a base or UNITED STATES PATENT OFFICE.

JOSEPH R. FINNEY, OF PITTSBURG, PENNSYLVANIA.

ELECTRIC-ARC L-AMP.

SPECIFICATION forming part of Letters Patent No. 268,394, dated December 5, 1882, I Application filed August 12, 1882. (K0 model.)

To all whom it may concern:

Be it known that I, JosEPn It. FINNEY, of Pittsburg, in the county of Allegheny and State of Pennsylvania, haveinvented a new and useful Improvement in Electric-Arc Lamps; and I do hereby declare the following to be a full, clear, and exact description thereof, reference being had to the accompanying drawings, forming a part of this specification, in which Figure l is a side elevation of my improved electric-arc lamp, the frame and the carbonfeed rod being broken, for greater clearness of illustration. Fig. 2 is a vertical sectional view of the upper arm of the frame. Fig. 3 is a cross-section showing the connection of the wires to the bracket-piece. Fig. at is a vertical section of the lower end of the frame and of the lower-carbon holder.

Like letters of reference indicate like parts in each.

The frame a of the lamp is a hollow tube, bent to the proper shape. It is preferably bracket-piece, b, by a suitable sleeve or clamp, c. The upper arm, (I, of the frame a is hollow and is formed of iron. Attached to its outer end by a screw-thread or otherwise is a sleeve, e, formed of brass or other diamagnetic material, the bore of which is larger than the diameter of the upper-carbon rod f, and at the ends is reduced in diameter by the insertion of the sleeves e. The bore of the sleeves e is of sufficient size to permit the easy passage of the rod f through them.

Secured in the sleeve 0, preferably at its lower end, by means of a suitable collar, g, is a contact-spring, g, which, bearing on the rod, establishes a constant electric connection between the sleeve 0 and the rod f, and thereby prevents sparking.

In the bore of the arm d, which is screwthreaded either partly or throughout its entire length, is a threaded iron-rod, h. At the lower end of the frame a is a vertical iron sleeve, 6, having alarge central bore, in which is placed an insulating-tube, 7c. The upper end of the tube is bored out to a larger diameter, as at k, and a spiral spring, I, is placed therein.

Extending vertically through the bore of the tube 70 is a rod, m, the upper end of which projects above the end of the sleeve t and is there provided with a screw-thread, upon which is screwed the lower-carbon holder 0. The spring 1 encircles the rod m and bears upwardly against the lower surface of the carbon-holder 0. The circuit-wires p and at, extending from the poles of the machine or other source of electricity, are attached to binding-screws p a. From the binding-screws the wires extend through the base or bracket piece 0 to the frame a, where they pass through a hole, a. Thence the wire 1) passes up through the bore of the frame a to the hole a near the arm cl, where, passing through the hole c it is wound around the arm (I in any suitable number of coils, and terminates at the sleeve 0. The wire it passes down through the frame a to the lower sleeve, i, where it passes out through the hole (0 up through the hole t in the shade-holder i, and is then wound around the sleeve 70 in any desired number of coils, and terminates in a hole in the lower-carbon holder at 0. The carbons are shown at q q and are secured in the carbon-holders 0 and r by set-screws o r.

The operation of my improved lamp is as follows: The rod IL is adjusted near to but not in contact with the rod f. This distance is determined by the strength of the current which is supplied to the circuit. The arm d and rod it constitute the core ofan electro-magnet, said core being magnetized by the passage of the current through the coils of the circuit-wire p. The magnetism of the core acting on the rod fstops its descent in the sleeve 0 when the circuit is established. The burning off of the carbon points q q decreases the magnetism of the core, and permits the rod fto slide until the carbon points q (1 again come in contact. 7

The establishment of the circuit causes the descent of the rod f to be stopped, and at the same time the passage of the current through the coils of the wire 11. around the sleeve 7t magnetizes the sleeve, which constitutes thus the core ofan electro-magnet, which, acting on the lower-carbon holder 0, draws it down against the pressure of the spring I, separating the points (1 q and establishing the are. This operation is repeated whenever, through the burning off of the carbon points, the current is weakened sufficiently to demagnetize the cores of the electro-magnets and permit the sliding of the rodfand the raising of the lower-carbon holder 0 by means of the spring I.

When the frame a is composed of iron the whole frame, with the sleeves d and i, constitutes the core of an electro-magnet formed by the wrapping of one or both of the circuit-wires thereon. I prefer, however, to construct the lamp as shown in the drawings,in which both of the sleeves are wrapped with the circuitwires.

If desired, the upper sleeve, d, may be formed by bending the upper end of the frame a at a right angle.

I prefer to make the rod h adjustable, as shown but it need not necessarily beso, as it may be set permanently in a fixed position when the lamp is designed to be used on acirunit of determined strength.

My improved lamp, especially when made of gas-pipe, as stated, is very cheap in construction, is simple and efficient in operation, easily repaired, and requires but little attention when 111 use.

I have shown and described the core of the upper electro-magnet as constituted of the arm at and rod h. It may, however, consist of the arm (I alone, by making its threaded stem d of suflicient length to enter the bore of the sleeve 6. The adjustment of the core with reference to the carbon-feed rod in such case would be effected by screwing the sleeve in or out the required distance on the stem d.

On the lower end of the red I prefer to place a tension-nut, m, for the purposes of properly tensioning the spring to the strength of the current, and of regulating the length of the arc. The same thing, however, may be accomplished by screwing the lower-carbon holder up or down on the rod m.

What I claim as my invention, and desire to secure by Letters Patent, is-

1. In an electric-arc lamp, the combination of a carbon-feed rod loosely inserted in a sleeve, with a core of an electromagnet entering the sleeve in close contiguity to but not in contact with the feed-rod, substantially as and for the purposes described.

2. In an electric-arc lamp, the combination of acarbon-feed rod loosely inserted in a sleeve, with an electro-magnet having an adjustable core, which enters the bore of said sleeve, substantially as and for the purposes described.

3. In an electric-arc lamp, the combination of aearbon-feed rod loosely inserted in a sleeve, having a bore somewhat larger than the diameter of the rod, with a contact-spring secured in the bore by means of a collar, substantially as and for the purposes described.

In testimony whereofI have hereunto set my hand this 9th day of August, A. D. 1882.

JOSEPH It. FINNEY.

Witnesses:

'1. B. KERR, JAMES H. Pou'rn. 

